**Explanation:**

A common noun is a type of noun that refers to a general or non-specific person, place, or thing. It is not capitalized unless it begins a sentence. Here is a detailed explanation of why option 'A' is the correct answer:

**a) Names any person, place, or thing:**
- A common noun can refer to any person, place, or thing without specifying a particular one. For example, the word "dog" is a common noun because it refers to any dog in general, not a specific dog.
- Similarly, words like "city," "book," and "teacher" are common nouns because they can refer to any city, book, or teacher in general.

**b) Names a specific person, place, or thing:**
- This option is incorrect because a common noun does not name a specific person, place, or thing. It refers to a general category rather than a particular one.
- For example, "dog" is a common noun that refers to any dog, while "Max" or "Bella" are proper nouns that refer to specific dogs.

**c) Names things you can see or touch:**
- This option is incorrect because common nouns can also refer to abstract concepts or intangible things that cannot be seen or touched.
- For instance, words like "happiness," "love," and "freedom" are common nouns because they represent ideas, qualities, or feelings.

**d) Names ideas, qualities, or feelings that cannot be seen or touched:**
- This option is partially correct because common nouns can indeed name ideas, qualities, or feelings that cannot be seen or touched. However, it does not encompass the full range of common nouns, as they can also refer to people and tangible objects.
- Examples of common nouns that represent ideas or qualities are "intelligence," "beauty," and "honesty."

In conclusion, option 'A' is the correct answer because a common noun names any person, place, or thing in a general or non-specific sense, regardless of whether it can be seen or touched.